Acer Aspire One came with McAfee, now firewall shuts off and can not access internet at all.

My Mother recently purchase the Acer Aspire One and it came with McAfee Internet Security on it. The system will connect to our wireless router, however not to the internet. The Firewall seems to be connecting and then almost instantly disconnects. I would like to uninstall McAfee if this problem is likely to persist, but I have tried many ways people say to fix this issue and can't even uninstall without having internet.